Currying_and_Compositon.php

<?php

require '/home/thomas/projects/functional-php/vendor/autoload.php';

//Manually currying
$test = function($start){
    return function($length) use ($start){
        return function($string) use ($start, $length){
            return substr($string, $start, $length);
        };
    };
};
$new = $test(0);
$new2 = $new(2);
var_dump($new2('testing'));

//Composition
function compose($a, $b){
    return function() use ($a, $b){
        $args = func_get_args();
        return $b(call_user_func_array($a, $args));
    };
}
$a = function($val){ return str_word_count($val); };
$b = function($val){ return $val - 2; };
$c = compose($a, $b);

var_dump($c('How many word does this sentence contain'));


use Functional as F;
$prods = array(
    array("sku" => 1234, "weight" => 1, "price" => '4.50', "qty" => 10, "cost" => 3.75),
    array("sku" => "abcd", "weight" => 0.5, "price" => '10', "qty" => 0, "cost" => 10),
    array("sku" => "shirt", "weight" => 0.1, "price" => '30', "qty" => 45, "cost" => 25),
    array("sku" => "shoes", "weight" => 2, "price" => '400', "qty" => 1, "cost" => 200)
);
function functionalSort($collection, $callback){
    uasort($collection, $callback);
    return $collection;
}
$mostExpensiveProduct = F\first(
    functionalSort(
        F\Pluck($prods, "price"),
        function($a, $b){
            return $a < $b;
        }
    )
);
var_dump($mostExpensiveProduct);
$maxSalesAvailable = F\reduce_left(
    $prods,
    function($value, $idx, $collection, $result){
        return $result + $value['qty'] * $value['price'];
    }
);
var_dump($maxSalesAvailable);
$mostProfitAvailableFunc = function($cost, $price, $qty){
    return ($price * $qty) - ($cost * $qty);
};
$maxProfitAvailable = F\sum(
    F\zip(
        F\pluck($prods, 'cost'),
        F\pluck($prods, 'price'),
        F\pluck($prods, 'qty'),
        $mostProfitAvailableFunc
    )
);
var_dump($maxProfitAvailable);
$test = function(){
    foreach(range(2,10) as $x){
        yield $x;
    }
};
var_dump(iterator_to_array($test()));